See also

IPC (International Patent Classification)

The IPC (International Patent Classification) is one of the
most important tools available to people who want to search patent databases.
It divides the world of technology up into over 70 000 categories. Whatever
your technical field, you can use the IPC to zoom in to patent documents
relevant to your field of work.

The IPC is a hierarchical system, with layers of increasing
detail. Here is an example:

New patent documents

When a patent office publishes a patent application or grants a patent, it classifies the invention using the version of the IPC in force at the time.

Reclassification of older documents

Revisions to the IPC generally take place once a year. Whenever the IPC is changed, older documents published under an
earlier version are reclassified. In other words, you can search all the
documents in patent databases by using the symbols of the latest IPC version.

Additional definitions

Definitions are being developed for the IPC to help understanding the scope of and the relevant references for a given subclass. In the areas where they
are ready, they are made available to the public in the electronic layer of the
new IPC.

Administration

WIPO is in charge of the administration of the IPC
classification schemes. The text of the latest version of the IPC, including
definitions, where available, can be found on the WIPO website .

All documents classified according to the IPC are stored in
a Master Classification Database (MCD), managed by the EPO. This database
supplies the IPC data for, among others, Espacenet.